Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description goes beyond them by disclosing a billing trait no annotation carries: 'Costs 1 credit per record returned (minimum 2)', plus the default-snapshot behavior when date is omitted — meaningful operational context for a paid, open-world search.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight clauses, front-loaded with scope, then cost, then routing. No filler, no repetition of schema text — every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Coverage is complete for a 12-param search tool: scope, default-snapshot semantics, cost model, filter dimensions, and sibling routing are all present, while an output schema handles return values and annotations handle safety.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description adds value by tying page_size directly to cost ('keep page_size to what you need') and naming the filterable dimensions (app, store, platform, chart, country, category), which maps semantics to billing behavior rather than merely restating field docs.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a precise verb+resource ('Search stored daily top-chart snapshot records from the iOS App Store and Google Play') and immediately scopes it against the two obvious siblings. An agent can distinguish this from datasets_apps_search and datasets_apps_reviews_search without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes to alternatives with their selection conditions ('use datasets_apps_search for app records or datasets_apps_reviews_search for stored reviews'), and adds the credit-cost constraint that shapes how to call it (keep page_size minimal). Nothing about when-to-use is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.